Study of a clinical phenotype is important both for identifying affected mice and also to detect progressive changes with age. At all stages of disease development, histopathologic analysis is a critical research component for determination of precise physical changes, correlation with functional changes, and localization of gene and protein expression. The Jackson Laboratory (TJL) eye investigators use diverse sophisticated histological techniques to obtain accurate, informative data on eye morphology and histopathology. However, continued expansion of eye research at TJL has created a demand for histology services that is straining the capacity of TJL's resources to provide these services, preventing further growth of the Laboratory's eye research programs. The proposed Histology Module will provide a skilled histologist dedicated to the support of eye research at TJL, and additional histology equipment, ensuring that the histology needs of the eye group are met and allowing continued research growth. Electroretinographic (ERG) analysis is also an essential component of eye research at TJL, because of its ability to identify and characterize functional abnormalities indicative of ocular disorders. ERG analysis at TJL is currently performed in the Eye Mutant Resource, a program to identify, characterize, and map mouse eye mutations and is a critical component of that program. However, the significant recent expansion of TJL's individual eye research programs, together with increased screening needs of the Eye Mutant Resource and other large-scale TJL programs, have created a demand for ERG testing that cannot be met by existing resources. This in turn hinders continued progress in eye research at TJL. The proposed ERG Module will provide a research assistant dedicated to performing ERG analyses for ocular research projects, using ERG equipment recently purchased by TJL. This will ensure the continued expansion of the eye research programs of individual TJL investigators and will also support screening for ocular disorders in other programs at TJL. It is anticipated that both the histology and ERG modules will help attract new scientists to eye research. [unreadable] [unreadable]